Yeah, I kinda figured it was along one of the Indy greenways, either the White River or the Fall Creek Parkway. Also, I feel your pain when it comes to that section of "dusty 12's"; most of the trails in the general Chicago area are surfaced with compacted "limestone screenings," the final dirt and dust left over from the sorting of different size rocks during the limestone crushing process. They're OK if there's regular rain fall during the Summer months, but if we have a dry spell they get extremely dusty and, as you say, that stuff is murder on the drive train. As a protective measure, I ride my regularly geared road bike only during periods when the surface is well settled. But I pull out a single speed conversion for the dusty times because it's much easier to maintain.